Framework for injecting a script-generated section into a subreddit sidebar.

sidebar_updater.py

#!/usr/bin/env python3

##########
# Config #
##########

oauth_key = ""
oauth_secret = ""
username = ""
password = ""
useragent = ""

subreddit = ""
delimiter = "######"
cache_file = "old_sidebar.md"
force_update = False

def create_sidebar_insert():
	return ""

##############
# Code stuff #
##############

import config as c
import praw_script_oauth as reddit
from praw.errors import *
import html
from requests.exceptions import HTTPError

# Reddit interaction

def get_sidebar(sub):
	try:
		settings = sub.get_settings()
		if "description" in settings:
			return html.unescape(settings["description"])
	
	except (ModeratorRequired, ModeratorOrScopeRequired):
		print("Error: Mod authorization required")
	except HTTPError as e:
		code = e.response.status_code
		if code == 403:
			print("Error: Mod authorization required (HTTP 403)")
		else:
			print("Error: Failed to load page, {} ({}) returned by server".format(code, e.response))
		
	return None

def set_sidebar(sub, sidebar):
	try:
		sub.update_settings(description=sidebar)
		return True
	
	except (ModeratorRequired, ModeratorOrScopeRequired):
		print("Error: Mod authorization required")
	except HTTPError as e:
		code = e.response.status_code
		if code == 403:
			print("Error: Mod authorization required (HTTP 403)")
		else:
			print("Error: Failed to load page, {} ({}) returned by server".format(code, e.response))
		
	return False

def sidebar_inject(sidebar, to_inject):
	inject_start = sidebar.find(delimiter)
	inject_end = sidebar.rfind(delimiter)
	inject_end = sidebar.find("\n", inject_end)
	inject_end = len(sidebar) if inject_end == -1 else inject_end + 2
	if inject_start == -1 or inject_start == inject_end:
		return sidebar
	
	sidebar_1 = sidebar[:inject_start]
	sidebar_2 = sidebar[inject_end:]
	
	return sidebar_1 + \
		delimiter+" START AUTO-GENERATION, DO NOT TOUCH\n\n" + \
		to_inject + "\n\n" + \
		delimiter+" END AUTO-GENERATION\n\n" + \
		sidebar_2

# Caching

def load_local_sidebar():
	try:
		with open(cache_file, "r") as f:
			return f.read()
	except:
		print("Sidebar save failed or none exists")
		return None

def save_local_sidebar(sidebar):
	with open(cache_file, "w") as f:
		f.write(sidebar)

# Main

def main():
	print("Generating sidebar")
	sidebar_insert = create_sidebar_insert()
	if not sidebar_insert:
		print("  No insert provided")
		return
	
	# Check for local changes
	old_sidebar_insert = load_local_sidebar()
	if not force_update and sidebar_insert == old_sidebar_insert:
		print("  No change!")
		return
	
	# Update sidebar
	print("Connecting to Reddit")
	r = reddit.connect(oauth_key, oauth_secret, username, password, useragent=useragent, oauth_scopes={"read", "modconfig"})
	if r is None:
		print("  Instance creation failed")
		return
	sub = r.get_subreddit(subreddit, fetch=False)
	
	sidebar = get_sidebar(sub)
	if sidebar is None:
		return
	
	print("Updating sidebar")
	new_sidebar = sidebar_inject(sidebar, sidebar_insert)
	if force_update or new_sidebar != sidebar:
		if set_sidebar(sub, new_sidebar):
			save_local_sidebar(sidebar_insert)
	else:
		print("  No change!")
	
if __name__ == "__main__":
	main()